Which riots are you referring to as "the most violent riots"?
How far back in time do we have to go back to find riots on a scale like these ones? In the UK of course (Swing riots? 19th century?).
My point is that if the situation has deteriorated this much, and riots at this scale are not common a occurrence in the UK, and none of those involved have and economical or social segregation problems, we are left with other alternatives, e.g. it is not lack of education, it is worst is an excess of the wrong type of education and the wrong ethical code been used.
These kids were acting coordinated, very well coordinated in fact, and almost all of them knew exactly when it become too dangerous to go and commit criminal acts again. The patterns of attacks and how they were acting in front of the police were rather scary once you look at the images and follow the places and timings of the attacks.
It is the new ways of mob mentality, much more fluid and with instant communications between individual components, it has been demonstrated in a much bigger scale in the Arab countries, and we have just seen a snippet of it here.
Just by waving this off and not analysing the situation further we will allow the problem to get much worst. In this scenario people shouting "these are just criminals" have their heads as stuck in the sand as much as those going "poor kids, society has let them down".